Method for erasing split-gate flash memory
US5978274A · kind A · utility
Assignees
Inventor
Key dates
| Filing date | Aug 3, 1998 |
| Grant date | Nov 2, 1999 |
| Priority date | — |
| Expiry date | Aug 3, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C16/14
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method of erasing a split gate flash memory cell is provided, which can be used in the operation of a split gate flash memory cell to increase the number of its rewritable cycles. The improvement is remarkable especially for flash memory cells while its floating gate channel length is under a 0.4 .mu.m-feature size. The erasing method includes the steps of: (i) applying a negative voltage to the control gate and applying a positive voltage to the drain to form a forward electrical field between the drain and the control gate; and (ii) applying a positive voltage to the source to reduce a voltage difference between the drain and the source, so that electrons in the floating gate are discharged under the effect of the forward electrical field generated by the Fowler-Nordheim tunneling effect, and hot holes can be reduced and prevented from accumulating in a tunnel oxide between the floating gate and the drain, thereby erasing the split-gate flash memory cell, and increasing the number of rewritable cycles for the flash memory cell.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.